Portable power supply



FIG. 1 is an isometric view of a portable power supply according to the design;

FIG. 2 is a top elevation of the portable power supply shown in FIG. 1;

FIG. 3 is a front elevation of the portable power supply shown in FIG. 1;

FIG. 4 is a bottom elevation of the portable power supply shown in FIG. 1;

FIG. 5 is a rear elevation of the portable power supply shown in FIG. 1;

FIG. 6 is a right side elevation of the portable power supply shown in FIG. 1; and,

FIG. 7 is a left side elevation of the portable power supply shown in FIG. 1. 

The ornamental design for portable power supply, as shown. 